Hello there. I'm building a live edge coffee table and I have all the components cut for the table top and legs, but the legs are splayed out at a 22° angle and I plan on using a spanner (the green bar in the image) to go through the legs using a through mortise and tenon joint then securing them with a tusk tenon. My question is, how do I make the mortise being that it has to follow the 22° angle in order for it to be parallel to the table top and floor? Thank you in advance.